1. Technical Field
The present invention relates to a wavelength conversion element, a light source device, and a projector.
2. Related Art
In the related art, there is a projector including a light source device, a light modulation device that modulates light emitted from the light source device and forms an image according to image information, and a project ion optical device that enlarges and projects the formed image on a projection surface such as a screen. As the light source device used in such a projector, a light source device having a solid-state light source and a fluorescent substance layer is known (for example, see JP-A-2014-137973).
The light source device disclosed in JP-A-2014-137973 has a reflection layer, a metal bump (bonding material), and a substrate in addition to the solid-state light source and the fluorescent substance layer. The reflection layer is provided on a surface opposite to a surface on which excitation light is incident from the solid-state light source of the fluorescent substance layer. The bonding material is disposed between the substrate and the reflection layer, and the bonding material supports the fluorescent substance layer and the reflection layer on the substrate. Therefore, the heat of an irradiation region irradiated with excitation light in the fluorescent substance layer is transmitted to the substrate via the bonding material, and the heat of the fluorescent substance layer is radiated by the substrate.
When excitation light is incident on the fluorescent substance layer (wavelength conversion portion) described in JP-A-2014-137973, in a case where the wavelength conversion portion is viewed along an incident direction of light, excitation light may be incident on a region outside a region (hereinafter, may be referred to as a bonding region) in which the bonding material is disposed at the wavelength conversion portion. As described above, since no bonding material is disposed on a surface opposite to the outer region at the wavelength conversion portion, when excitation light is incident on the outer region, the heat of the wavelength conversion portion in the outer region cannot be transmitted to the substrate via the bonding material. Therefore, there is a problem that a temperature of the wavelength conversion portion increases and wavelength conversion efficiency of incident excitation light deteriorates.